Sugarcane is one of the most photosynthetic efficient cultivated crops. Sugarcane average annual yields in Brazil, world's largest producer, range from 80 to 120 tons/ha. Yet, the productivity potential of 300 tons of biomass per hectare has been suggested. Alexander, THE ENERGY CANE ALTERNATIVE (Elsevier, 1985).
The utilization of biomass has been the subject of strong interest recently, particularly with respect to the efforts to develop methods to produce alternate fuels that use non-starch, non-food-related biomass, such as trees, grasses and waste materials, which would expand the available resource base for sugars and would lower cost sources. In Brazil, sugarcane mills have developed technologies for large-scale sucrose fermentation for producing fuel ethanol. In the 2006/2007 crop, approximately 18 billion liters of sugarcane-derived ethanol were produced. In addition to providing a renewable source of fuel, sugarcane-based fuel provides a means for reducing CO2 emissions.
Over the centuries, sugarcane was cultivated almost solely as a source of sucrose, which accumulates at high concentrations in the stem internodes. The sucrose then is extracted and purified in large mill factories, and is used as a raw material in food industries.
While sugarcane is photosynthetically efficient, the average productivity of commercial sugarcane plantations around the world is limited by the highly polyploid nature of the sugarcane genome, which renders sugarcane not amenable to most of the breeding techniques developed for diploid species. Because traditional breeding programs have provided limited success in producing high-yielding plants, cultivated sugarcane varieties are clones derived from interspecific crosses between Saccharum officinarum with its relatives, most often S. spontaneum but also S. sinense or S. barberi, whose progenies were backcrossed to S. officinarum. On the other hand, the emergence of molecular genetics approaches to manipulating plant genomes has offered researchers a means for developing crops with improved properties or traits, through introduction and expression of recombinant nucleic acid molecules in plants.